THE CHANGES OF GEOMAGNETIC TOTAL FIELD IN BEIJING AREA BEFORE AND AFTER THE 1976 TANGSHAN EARTHQUAKE

Abstract The aftershock zone of the 1976 Ms 7.8 Tangshan, China, earthquake remains seismically active, experiencing moderate events such as the 5 December 2019 Ms 4.5 Fengnan event. It is still debated whether aftershock sequences following large earthquakes in low-seismicity continental regions can persist for several centuries. To understand the current stage of the Tangshan aftershock sequence, we analyze the sequence record and separate background seismicity from the triggering effect using a finite-source epidemic-type aftershock sequence model. Our results show that the background rate notably decreases after the mainshock. The estimated probability that the most recent 5 December 2019 Ms 4.5 Fengnan District, Tangshan, earthquake is a background event is 50.6%. This indicates that the contemporary seismicity in the Tangshan aftershock zone can be characterized as a transition from aftershock activity to background seismicity. Although the aftershock sequence is still active in the Tangshan region, it is overridden by background seismicity.

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The mechanism of regional gravity changes before and after the Tangshan earthquake

Acta Seismologica Sinica ◽

10.1007/s11589-997-0058-3 ◽

1997 ◽

Vol 10 (4) ◽

pp. 497-500 ◽

Cited By ~ 2

Author(s):

Rui-Hao Li ◽

Jian-Liang Huang ◽

Hui Li ◽

Dong-Sheng Chen

Keyword(s):

Tangshan Earthquake ◽

Gravity Changes ◽

Before And After ◽

Regional Gravity

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Combination of Herbicide Band Application and Inter-Row Cultivation Provides Sustainable Weed Control in Maize

Agronomy ◽

10.3390/agronomy10010020 ◽

2019 ◽

Vol 10 (1) ◽

pp. 20 ◽

Cited By ~ 3

Author(s):

Donato Loddo ◽

Laura Scarabel ◽

Maurizio Sattin ◽

Antonio Pederzoli ◽

Chiara Morsiani ◽

...

Keyword(s):

Weed Control ◽

Weed Management ◽

Field Experiments ◽

Total Field ◽

Weed Density ◽

Silage Maize ◽

Application Systems ◽

Standard Management ◽

Before And After ◽

Herbicide Use

Herbicides have facilitated weed management but their incorrect use can lead to environmental contamination. Reducing herbicide use by limiting their application to a band along the crop row can decrease their environmental impact. Three field experiments were conducted in North-eastern Italy to evaluate herbicide band application systems integrated with inter-row hoeing for silage maize. Post-emergence herbicide band application (sprayed area 50% of total field; herbicide dose 50% of that recommended, application with an inter-row cultivator prototype) was compared with pre-emergence band application (sprayed area 33% of total field; herbicide dose 33% of that recommended, application with a seeder) and pre-emergence broadcast application (sprayed area 100% of total field; full recommended herbicide dose, application with a boom sprayer) that is standard management for maize. Weed density and composition were evaluated before and after post-emergence herbicide application and at crop harvest. Crop yield was also recorded. Weed density in untreated areas ranged between 5 and 15 plants m−2 in the different experiments. Optimal weed control and good yields were achieved without significant differences between all treatments. Herbicide band application can provide optimal weed control in silage maize, at the same time allowing a relevant reduction of herbicide input.

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